Ágnes M. Móricz
Plant Protection Institute, Centre for Agricultural Research, ELKH, Herman O. Str. 15, 1022, Budapest, Hungary
This email address is being protected from spambots. You need JavaScript enabled to view it.
HPTLC hyphenations enable fast and high-throughput screening for bioactive compounds of complex matrices as well as their characterization. However, in several cases the identification of the effective compounds are impossible due to their insufficient separation or low abundance. Here are three solutions. Overpressured layer chromatography (OPLC) as a pump-driven forced flow technique enabled a longer development distance, thus the partial separation of two tansy root compounds, which were not separable by conventional HPTLC [1]. The OPLC-bioassays and OPLC-DART-HRMS showed six compounds responsible for different bioactivity and allowed the identification of four polyacetylenes. Moreover, using irregular particle layers, the separation time was approximately halved by OPLC, if compared to HPTLC. Two closely related constitutional isomers, oleanolic acid and ursolic acid are co-migrated in normal phase HPTLC. These compounds are not distinguishable by HRMS and give a common inhibition zone in the HPTLC-bioassays. The two-dimensional liquid chromatographic hyphenation, the heart-cutting HPTLC-HPLC-DAD-MS via an elution head-based interface enabled the separation and assignment of both isomers in the lemon balm leaf [2]. Ursolic acid was more abundant and is mainly responsible for the bioeffects. In bilateral band compression (BBC) the samples are applied in band, and after development, the lanes are compressed in a perpendicular direction from both sides with appropriate solvent. HPTLC-BBC resulted in more than six times higher peak height and area, however, the noise level and the RSDs were increased as well [3]. OPLC-BBC-bioassay allowed the bio-detection of the minor antibacterial components of thyme essential oil, which were not detectable by a conventional OPLC-bioassay process. This work was partially funded by the National Research, Development and Innovation Office of Hungary (NKFIH K128921).
[1] Á.M. Móricz, T.T. Häbe, P.G. Ott, G.E. Morlock, J. Chromatogr. A 1603 (2019) 355-360.
[2] Á.M. Móricz, V. Lapat, G.E. Morlock, P.G. Ott, Talanta 219 (2020) 121306.
[3] Á.M. Móricz, E. Mincsovics, P.G. Ott, J. Liq. Chromatogr. Relat. Technol. 43 (2020) 300-304.
